• # question_answer Two blocks each of mass m in the device are pulled by a force $F=\text{ }mg/2$ as shown in figure. All the contact surfaces are smooth. The acceleration of block A is A) $\frac{\sqrt{5}}{4}g$ B) $\frac{\sqrt{3}}{2}g$ C) $\frac{g}{2}$ D) $\frac{g}{4}$

 For the system as a whole, $\frac{mg}{2}=2m({{a}_{x}})$ $\therefore$      ${{a}_{x}}=g/4$ For block A,$\frac{mg}{2}=m{{a}_{y}}$ $\therefore$      ${{a}_{y}}=g/2$ Thus ${{a}_{A}}=\sqrt{a_{x}^{2}+a_{y}^{2}}=\sqrt{{{\left( \frac{g}{4} \right)}^{2}}+{{\left( \frac{g}{2} \right)}^{2}}}$ $=\frac{\sqrt{5}}{4}g$